The prior art includes various conveyors for conveying parts to be painted through a spray or application paint booth, including conveyors specifically designed for powder paint application booths. As used herein, the term “powder paint” is generic to any protective powder coating, including but not limited to powder paint applied by the automotive industry.
Conveyors for conveying parts through a paint booth typically include a continuous steel chain which must be lubricated to reduce wear of the chain. The parts to be conveyed are typically mounted on a skid which is conveyed through the paint booth by the chain and paint is applied to the part by paint applicators, including robotic paint applicators. Because of the wear problem with conventional steel chain and adherence of powder paint on the steel chain, particularly with the application of powder paint, stainless steel chain and sealed for life bearings have been used. However, this approach has not solved the problems associated with conveying parts through a powder paint application booth.
Another problem associated with the application of powder paint is recovery of powder paint from the paint application booth. As will be understood by those skilled in this art, a portion of any paint directed to a part to be painted by paint applicators will not be applied to the part and such paint is sometimes referred to as overspray or excess paint. The recovery of excess paint is a particular problem with powder paint. Another problem is that the powder paint adheres to most exposed surfaces, such as the belt of a conveyor. Thus, vacuum cleaners are provided at spaced locations, but the powder paint recovered by vacuum cleaners is not reusable because it generally includes contaminants.
The prior art has also proposed conveyors having a continuous stainless steel belt to reduce adherence of powder paint to the belt and the parts are conveyed on a skid received on the continuous moving stainless steel belt. Excess powder paint is then vacuumed from the belt as described above. Although the stainless steel belt is very thin, about 1 mm in thickness, the belt is about a yard in width (e.g., 38 inches), creating other problems. First, powder paint still collects on the stainless steel belt and the wide stainless steel belt is generally very expensive and easily damaged. Further, it is not possible to walk over the wide stainless steel belt, requiring workers in the powder paint application booth to continuously walk around the wide stainless steel belt for maintenance, etc. The wide stainless steel belt also interferes with the air flow through the paint application booth and thus reduces collection of excess powder paint from the booth.
There is, therefore, a longstanding need for a conveyor for powder paint application booths which solves the problems associated with the prior art described above and which also improves the airflow and efficiency of the powder collection system.